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Re: [Xen-ia64-devel] [patch 2/7] IA64: Kexec: Use a separate RID for EFI



This patch is a first cut at implementing Yamahata-san's idea of
assigning a special RID for use with EFI mappings. The basic
idea is to switch to this RID, which is in the range reserved
for the hypervisor, before making EFI, PAL or SAL calls. The page
fault handler where the identity mapping checks for this RID, if
present it does the identity mapping, else it just follows the normal
mapping rules. In this way, VMX domains should not be able to access
this memory, and they should be able to use the virtual addresses
that are used by EFI for their own purposes.

The patch does seem to work, in the sense that the EFI mappings work.
I have not stress tested it to see if domains can still do nefarious
things. I would appreciate a review of this.

Cc: Tristan Gingold <tgingold@xxxxxxx>
Cc: Isaku Yamahata <yamahata@xxxxxxxxxxxxx>
Signed-off-by: Simon Horman <horms@xxxxxxxxxxxx>

---
Tue, 23 Oct 2007 15:47:27 +0900

* Don't use #ifndef XEN to denote changes to SAL, PAL and EFI macros,
  as this means that the macros have to be duplicated which leads to
  a very bulky patch. Instead, define the new functionality as
  XEN_EFI_RR_SAVE and XEN_EFI_RR_RESTORE (previously EFI_RR_SAV and
  EFI_RR_RESTOR) and put these macros straight into the existing macros -
  this should be obvious enough for future up-porters.

  As suggested by Alex Williamson.

* Break header changes out into a separate patch

* Break macro definitions out into a separate patch and
  put them in efi.h instead of pal.h. Documentation of how the
  EFI RID is selected is included in this new patch.

* Use a uniform defineition of XEN_EFI_RID in assembly and C code

Mon, 29 Oct 2007 13:43:33 +0900

* Put assembly code into a separate patch

* C code is no longer needed with the new assembly code

Mon, 12 Nov 2007 12:02:59 +0900

* Trivial upport to ia64/xen-unstable.hg 16287:b235b68a0f4f

Index: xen-unstable.hg/xen/include/asm-ia64/linux/asm/sal.h
===================================================================
--- xen-unstable.hg.orig/xen/include/asm-ia64/linux/asm/sal.h   2007-11-12 
11:00:23.000000000 +0900
+++ xen-unstable.hg/xen/include/asm-ia64/linux/asm/sal.h        2007-11-12 
12:02:37.000000000 +0900
@@ -52,9 +52,12 @@ extern spinlock_t sal_lock;
 # define SAL_CALL(result,args...) do {                         \
        unsigned long __ia64_sc_flags;                          \
        struct ia64_fpreg __ia64_sc_fr[6];                      \
+       int rr6, rr7;                                           \
        ia64_save_scratch_fpregs(__ia64_sc_fr);                 \
        spin_lock_irqsave(&sal_lock, __ia64_sc_flags);          \
+       XEN_EFI_RR_SAVE(rr6, rr7);                              \
        __SAL_CALL(result, args);                               \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                           \
        spin_unlock_irqrestore(&sal_lock, __ia64_sc_flags);     \
        ia64_load_scratch_fpregs(__ia64_sc_fr);                 \
 } while (0)
@@ -62,18 +65,24 @@ extern spinlock_t sal_lock;
 # define SAL_CALL_NOLOCK(result,args...) do {          \
        unsigned long __ia64_scn_flags;                 \
        struct ia64_fpreg __ia64_scn_fr[6];             \
+       int rr6, rr7;                                   \
        ia64_save_scratch_fpregs(__ia64_scn_fr);        \
        local_irq_save(__ia64_scn_flags);               \
+       XEN_EFI_RR_SAVE(rr6, rr7);                      \
        __SAL_CALL(result, args);                       \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                   \
        local_irq_restore(__ia64_scn_flags);            \
        ia64_load_scratch_fpregs(__ia64_scn_fr);        \
 } while (0)
 
 # define SAL_CALL_REENTRANT(result,args...) do {       \
        struct ia64_fpreg __ia64_scs_fr[6];             \
+       int rr6, rr7;                                   \
        ia64_save_scratch_fpregs(__ia64_scs_fr);        \
        preempt_disable();                              \
+       XEN_EFI_RR_SAVE(rr6, rr7);                      \
        __SAL_CALL(result, args);                       \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                   \
        preempt_enable();                               \
        ia64_load_scratch_fpregs(__ia64_scs_fr);        \
 } while (0)
Index: xen-unstable.hg/xen/arch/ia64/linux-xen/efi.c
===================================================================
--- xen-unstable.hg.orig/xen/arch/ia64/linux-xen/efi.c  2007-11-12 
11:00:23.000000000 +0900
+++ xen-unstable.hg/xen/arch/ia64/linux-xen/efi.c       2007-11-12 
12:02:37.000000000 +0900
@@ -63,14 +63,18 @@ static efi_status_t                                         
                                  \
 prefix##_get_time (efi_time_t *tm, efi_time_cap_t *tc)                         
                  \
 {                                                                              
                  \
        struct ia64_fpreg fr[6];                                                
                  \
+       unsigned long rr6, rr7;                                                 
                  \
        efi_time_cap_t *atc = NULL;                                             
                  \
        efi_status_t ret;                                                       
                  \
                                                                                
                  \
        if (tc)                                                                 
                  \
                atc = adjust_arg(tc);                                           
                  \
        ia64_save_scratch_fpregs(fr);                                           
                  \
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
                  \
        ret = efi_call_##prefix((efi_get_time_t *) __va(runtime->get_time), 
adjust_arg(tm), atc); \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
                  \
+       ia64_set_rr(7, rr7);                                                    
                  \
        return ret;                                                             
                  \
 }
 
@@ -79,10 +83,13 @@ static efi_status_t                                         
                                \
 prefix##_set_time (efi_time_t *tm)                                             
                \
 {                                                                              
                \
        struct ia64_fpreg fr[6];                                                
                \
+       unsigned long rr6, rr7;                                                 
                  \
        efi_status_t ret;                                                       
                \
                                                                                
                \
        ia64_save_scratch_fpregs(fr);                                           
                \
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
                  \
        ret = efi_call_##prefix((efi_set_time_t *) __va(runtime->set_time), 
adjust_arg(tm));    \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
                \
        return ret;                                                             
                \
 }
@@ -92,11 +99,14 @@ static efi_status_t                                         
                                \
 prefix##_get_wakeup_time (efi_bool_t *enabled, efi_bool_t *pending, efi_time_t 
*tm)            \
 {                                                                              
                \
        struct ia64_fpreg fr[6];                                                
                \
+       unsigned long rr6, rr7;                                                 
                  \
        efi_status_t ret;                                                       
                \
                                                                                
                \
        ia64_save_scratch_fpregs(fr);                                           
                \
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
                  \
        ret = efi_call_##prefix((efi_get_wakeup_time_t *) 
__va(runtime->get_wakeup_time),       \
                                adjust_arg(enabled), adjust_arg(pending), 
adjust_arg(tm));      \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
                \
        return ret;                                                             
                \
 }
@@ -106,14 +116,17 @@ static efi_status_t                                       
                                        \
 prefix##_set_wakeup_time (efi_bool_t enabled, efi_time_t *tm)                  
                \
 {                                                                              
                \
        struct ia64_fpreg fr[6];                                                
                \
+       unsigned long rr6, rr7;                                                 
                  \
        efi_time_t *atm = NULL;                                                 
                \
        efi_status_t ret;                                                       
                \
                                                                                
                \
        if (tm)                                                                 
                \
                atm = adjust_arg(tm);                                           
                \
        ia64_save_scratch_fpregs(fr);                                           
                \
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
                  \
        ret = efi_call_##prefix((efi_set_wakeup_time_t *) 
__va(runtime->set_wakeup_time),       \
                                enabled, atm);                                  
                \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
                \
        return ret;                                                             
                \
 }
@@ -124,15 +137,18 @@ prefix##_get_variable (efi_char16_t *nam
                       unsigned long *data_size, void *data)                    
        \
 {                                                                              
        \
        struct ia64_fpreg fr[6];                                                
        \
+       unsigned long rr6, rr7;                                                 
                  \
        u32 *aattr = NULL;                                                      
                \
        efi_status_t ret;                                                       
        \
                                                                                
        \
        if (attr)                                                               
        \
                aattr = adjust_arg(attr);                                       
        \
        ia64_save_scratch_fpregs(fr);                                           
        \
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
                  \
        ret = efi_call_##prefix((efi_get_variable_t *) 
__va(runtime->get_variable),     \
                                adjust_arg(name), adjust_arg(vendor), aattr,    
        \
                                adjust_arg(data_size), adjust_arg(data));       
        \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
        \
        return ret;                                                             
        \
 }
@@ -142,11 +158,14 @@ static efi_status_t                                       
                                        \
 prefix##_get_next_variable (unsigned long *name_size, efi_char16_t *name, 
efi_guid_t *vendor)  \
 {                                                                              
                \
        struct ia64_fpreg fr[6];                                                
                \
+       unsigned long rr6, rr7;                                                 
                  \
        efi_status_t ret;                                                       
                \
                                                                                
                \
        ia64_save_scratch_fpregs(fr);                                           
                \
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
                  \
        ret = efi_call_##prefix((efi_get_next_variable_t *) 
__va(runtime->get_next_variable),   \
                                adjust_arg(name_size), adjust_arg(name), 
adjust_arg(vendor));   \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
                \
        return ret;                                                             
                \
 }
@@ -157,12 +176,15 @@ prefix##_set_variable (efi_char16_t *nam
                       unsigned long data_size, void *data)                     
        \
 {                                                                              
        \
        struct ia64_fpreg fr[6];                                                
        \
+       unsigned long rr6, rr7;                                                 
                  \
        efi_status_t ret;                                                       
        \
                                                                                
        \
        ia64_save_scratch_fpregs(fr);                                           
        \
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
                  \
        ret = efi_call_##prefix((efi_set_variable_t *) 
__va(runtime->set_variable),     \
                                adjust_arg(name), adjust_arg(vendor), attr, 
data_size,  \
                                adjust_arg(data));                              
        \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
        \
        return ret;                                                             
        \
 }
@@ -172,11 +194,14 @@ static efi_status_t                                       
                                        \
 prefix##_get_next_high_mono_count (u32 *count)                                 
                \
 {                                                                              
                \
        struct ia64_fpreg fr[6];                                                
                \
+       unsigned long rr6, rr7;                                                 
                  \
        efi_status_t ret;                                                       
                \
                                                                                
                \
        ia64_save_scratch_fpregs(fr);                                           
                \
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
                  \
        ret = efi_call_##prefix((efi_get_next_high_mono_count_t *)              
                \
                                __va(runtime->get_next_high_mono_count), 
adjust_arg(count));    \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
                \
        return ret;                                                             
                \
 }
@@ -187,15 +212,18 @@ prefix##_reset_system (int reset_type, e
                       unsigned long data_size, efi_char16_t *data)             
\
 {                                                                              
\
        struct ia64_fpreg fr[6];                                                
\
+       unsigned long rr6, rr7;                                                 
                  \
        efi_char16_t *adata = NULL;                                             
\
                                                                                
\
        if (data)                                                               
\
                adata = adjust_arg(data);                                       
\
                                                                                
\
        ia64_save_scratch_fpregs(fr);                                           
\
+       XEN_EFI_RR_SAVE(rr6, rr7);                                              
\
        efi_call_##prefix((efi_reset_system_t *) __va(runtime->reset_system),   
\
                          reset_type, status, data_size, adata);                
\
        /* should not return, but just in case... */                            
\
+       XEN_EFI_RR_RESTORE(rr6, rr7);                                           
                  \
        ia64_load_scratch_fpregs(fr);                                           
\
 }
 
Index: xen-unstable.hg/xen/include/asm-ia64/linux-xen/asm/pal.h
===================================================================
--- xen-unstable.hg.orig/xen/include/asm-ia64/linux-xen/asm/pal.h       
2007-11-12 11:09:55.000000000 +0900
+++ xen-unstable.hg/xen/include/asm-ia64/linux-xen/asm/pal.h    2007-11-12 
12:02:37.000000000 +0900
@@ -93,6 +93,9 @@
 
 #include <linux/types.h>
 #include <asm/fpu.h>
+#ifdef XEN
+#include <linux/efi.h>
+#endif
 
 /*
  * Data types needed to pass information into PAL procedures and
@@ -791,29 +794,41 @@ extern void ia64_load_scratch_fpregs (st
 
 #define PAL_CALL(iprv,a0,a1,a2,a3) do {                        \
        struct ia64_fpreg fr[6];                        \
+       unsigned long rr6, rr7;                         \
        ia64_save_scratch_fpregs(fr);                   \
+       XEN_EFI_RR_SAVE(rr6, rr7);                      \
        iprv = ia64_pal_call_static(a0, a1, a2, a3);    \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                   \
        ia64_load_scratch_fpregs(fr);                   \
 } while (0)
 
 #define PAL_CALL_STK(iprv,a0,a1,a2,a3) do {            \
        struct ia64_fpreg fr[6];                        \
+       unsigned long rr6, rr7;                         \
        ia64_save_scratch_fpregs(fr);                   \
+       XEN_EFI_RR_SAVE(rr6, rr7);                      \
        iprv = ia64_pal_call_stacked(a0, a1, a2, a3);   \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                   \
        ia64_load_scratch_fpregs(fr);                   \
 } while (0)
 
 #define PAL_CALL_PHYS(iprv,a0,a1,a2,a3) do {                   \
        struct ia64_fpreg fr[6];                                \
+       unsigned long rr6, rr7;                                 \
        ia64_save_scratch_fpregs(fr);                           \
+       XEN_EFI_RR_SAVE(rr6, rr7);                              \
        iprv = ia64_pal_call_phys_static(a0, a1, a2, a3);       \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                           \
        ia64_load_scratch_fpregs(fr);                           \
 } while (0)
 
 #define PAL_CALL_PHYS_STK(iprv,a0,a1,a2,a3) do {               \
        struct ia64_fpreg fr[6];                                \
+       unsigned long rr6, rr7;                                 \
        ia64_save_scratch_fpregs(fr);                           \
+       XEN_EFI_RR_SAVE(rr6, rr7);                              \
        iprv = ia64_pal_call_phys_stacked(a0, a1, a2, a3);      \
+       XEN_EFI_RR_RESTORE(rr6, rr7);                           \
        ia64_load_scratch_fpregs(fr);                           \
 } while (0)
 

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